Hitherto, plant growth-promoting agents having effects of, for example, promoting rhizogenesis of plants, preventing lodging, improving yield, cold resistance, and green color, enhancing good seedling, increasing the number of tiller buds (branches), promoting organ growth have been used in order to improve yields of plants.
For example, Patent Document 1 discloses that a tetrazoyloxime derivative is a useful plant growth-promoting agent.
In addition, Patent Document 2 discloses a composition containing a choline and hydroxyisoxazole for promoting rhizogenesis and good seedling of rice, and Patent Document 3 suggests an agent for promoting good seedling of rice, which contains 3-hydroxypyrazine or a derivative thereof as an active ingredient.
The substances disclosed in Patent Documents 1 to 3, however, have structures that totally differ from the structures of the compounds used as active ingredients in the present invention.
Among compounds used as active ingredients in the present invention, 1-piperonylpiperazine (1-(3,4-methylenedioxybenzyl)piperazine) and many analogs thereof, which are 1-substituted piperazine derivatives and analogs thereof, are used as manufacturing starting materials and commercially available (e.g., Patent Documents 4 and 5).
However, there has been no report demonstrating that the compounds used as active ingredients in the present invention have plant growth promoting effects.